Plasmonic enhancement of stability and brightness in organic light-emitting devices.

The field of plasmonics, which studies the resonant interactions of electromagnetic waves and free electrons in solid-state materials1, has yet to be put to large-scale commercial application2 owing to the large amount of loss that usually occurs in plasmonic materials3. Organic light-emitting devices (OLEDs)4-7 have been incorporated into billions of commercial products because of their good colour saturation, versatile form factor8 and low power consumption9, but could still be improved in terms of efficiency and stability. Although OLEDs incorporating organic phosphors achieve an internal charge-to-light conversion of unity10, their refractive index contrast reduces the observable fraction of photons outside the device to around 25 per cent11-13. Further, during OLED operation, a localized buildup of slow-decaying14 triplet excitons and charges15 gradually reduces the brightness of the device in a process called ageing16,17, which can result in 'burn-in' effects on the display. Simultaneously improving device efficiency and stability is of paramount importance for OLED technology. Here we demonstrate an OLED that uses the decay rate enhancement18 of a plasmonic system to increase device stability, while maintaining efficiency by incorporating a nanoparticle-based out-coupling scheme to extract energy from the plasmon mode. Using an archetypal phosphorescent emitter, we achieve a two-fold increase in operational stability at the same brightness as a reference conventional device while simultaneously extracting 16 per cent of the energy from the plasmon mode as light. Our approach to increasing OLED stability avoids material-specific designs19-22 and is applicable to all commercial OLEDs that are currently used for lighting panels, televisions and mobile displays.

Sound Source Localization by Cochlear Implant Recipients with Normal Hearing in the Contralateral Ear: Effects of Spectral Content and Duration of Listening Experience.

INTRODUCTION: Cochlear implant (CI) recipients with normal hearing (NH) in the contralateral ear experience a significant improvement in sound source localization when listening with the CI in combination with their NH-ear (CI + NH) as compared to with the NH-ear alone. The improvement in localization is primarily due to sensitivity to interaural level differences (ILDs). Sensitivity to interaural timing differences (ITDs) may be limited by auditory aging, frequency-to-place mismatches, the signal coding strategy, and duration of CI use. The present report assessed the sensitivity of ILD and ITD cues in CI + NH listeners who were recipients of long electrode arrays that provide minimal frequency-to-place mismatches and were mapped with a coding strategy that presents fine structure cues on apical channels. METHODS: Sensitivity to ILDs and ITDs for localization was assessed using broadband noise (BBN), as well as high-pass (HP) and low-pass (LP) filtered noise for adult CI + NH listeners. Stimuli were 200-ms noise bursts presented from 11 speakers spaced evenly over an 180° arc. Performance was quantified in root-mean-squared error and response patterns were analyzed to evaluate the consistency, accuracy, and side bias of the responses. Fifteen listeners completed the task at the 2-year post-activation visit; seven listeners repeated the task at a later annual visit. RESULTS: Performance at the 2-year visit was best with the BBN and HP stimuli and poorer with the LP stimulus. Responses to the BBN and HP stimuli were significantly correlated, consistent with the idea that CI + NH listeners primarily use ILD cues for localization. For the LP stimulus, some listeners responded consistently and accurately and with limited side bias, which may indicate sensitivity to ITD cues. Two of the 7 listeners who repeated the task at a later annual visit experienced a significant improvement in performance with the LP stimulus, which may indicate that sensitivity to ITD cues may improve with long-term CI use. CONCLUSIONS: CI recipients with a NH-ear primarily use ILD cues for sound source localization, though some may use ITD cues as well. Sensitivity to ITD cues may improve with long-term CI listening experience.

Energy harvesting of non-emissive triplet excitons in tetracene by emissive PbS nanocrystals.

Triplet excitons are ubiquitous in organic optoelectronics, but they are often an undesirable energy sink because they are spin-forbidden from emitting light and their high binding energy hinders the generation of free electron-hole pairs. Harvesting their energy is consequently an important technological challenge. Here, we demonstrate direct excitonic energy transfer from 'dark' triplets in the organic semiconductor tetracene to colloidal PbS nanocrystals, thereby successfully harnessing molecular triplet excitons in the near infrared. Steady-state excitation spectra, supported by transient photoluminescence studies, demonstrate that the transfer efficiency is at least (90 ± 13)%. The mechanism is a Dexter hopping process consisting of the simultaneous exchange of two electrons. Triplet exciton transfer to nanocrystals is expected to be broadly applicable in solar and near-infrared light-emitting applications, where effective molecular phosphors are lacking at present. In particular, this route to 'brighten' low-energy molecular triplet excitons may permit singlet exciton fission sensitization of conventional silicon solar cells.

Magnetic field dependence of singlet fission in solutions of diphenyl tetracene.

Magnetic field effects provide a convenient and specific probe of singlet exciton fission within optoelectronic devices. Here, we demonstrate that this tool may also be applied to screen potential fission material candidates in solution. We characterize the phenomenon in diphenyl tetracene (DPT), which shows strong fluorescence modulation and the expected field dependence in its transient decay as a function of concentration. Solution measurements may also be used to test for the presence of an intermediate charge transfer state, but we observe no changes to the field dependence of DPT singlet exciton fission in toluene relative to chloroform.

Singlet exciton fission photovoltaics.

Singlet exciton fission, a process that generates two excitons from a single photon, is perhaps the most efficient of the various multiexciton-generation processes studied to date, offering the potential to increase the efficiency of solar devices. But its unique characteristic, splitting a photogenerated singlet exciton into two dark triplet states, means that the empty absorption region between the singlet and triplet excitons must be filled by adding another material that captures low-energy photons. This has required the development of specialized device architectures. In this Account, we review work to develop devices that harness the theoretical benefits of singlet exciton fission. First, we discuss singlet fission in the archetypal material, pentacene. Pentacene-based photovoltaic devices typically show high external and internal quantum efficiencies. They have enabled researchers to characterize fission, including yield and the impact of competing loss processes, within functional devices. We review in situ probes of singlet fission that modulate the photocurrent using a magnetic field. We also summarize studies of the dissociation of triplet excitons into charge at the pentacene-buckyball (C60) donor-acceptor interface. Multiple independent measurements confirm that pentacene triplet excitons can dissociate at the C60 interface despite their relatively low energy. Because triplet excitons produced by singlet fission each have no more than half the energy of the original photoexcitation, they limit the potential open circuit voltage within a solar cell. Thus, if singlet fission is to increase the overall efficiency of a solar cell and not just double the photocurrent at the cost of halving the voltage, it is necessary to also harvest photons in the absorption gap between the singlet and triplet energies of the singlet fission material. We review two device architectures that attempt this using long-wavelength materials: a three-layer structure that uses long- and short-wavelength donors and an acceptor and a simpler, two-layer combination of a singlet-fission donor and a long-wavelength acceptor. An example of the trilayer structure is singlet fission in tetracene with copper phthalocyanine inserted at the C60 interface. The bilayer approach includes pentacene photovoltaic cells with an acceptor of infrared-absorbing lead sulfide or lead selenide nanocrystals. Lead selenide nanocrystals appear to be the most promising acceptors, exhibiting efficient triplet exciton dissociation and high power conversion efficiency. Finally, we review architectures that use singlet fission materials to sensitize other absorbers, thereby effectively converting conventional donor materials to singlet fission dyes. In these devices, photoexcitation occurs in a particular molecule and then energy is transferred to a singlet fission dye where the fission occurs. For example, rubrene inserted between a donor and an acceptor decouples the ability to perform singlet fission from other major photovoltaic properties such as light absorption.

Surgical Outcomes of Modified Technique for Transcutaneous Bone Conduction Hearing Aid Implantation.

OBJECTIVE: To detail a modified surgical technique for implantation of the Osia 2 Bone Conduction Hearing Aid (BCHA) system and to assess intra- and postoperative outcomes of this technique. METHODS: A retrospective review was performed for cases undergoing implantation of an Osia 2 BCHA at a tertiary academic medical center. Modifications were made to the surgical procedure including: horizontal or curvilinear incisions, placement of the osseointegrated screw slightly superior to the plane of the external auditory canal, and double layer wound closure. Data regarding outcomes including demographics, incision type, surgical time, drilling requirements, and complications were collected using the electronic medical record. RESULTS: A total of twenty-eight cases were evaluated with 57.1% and 42.9% utilizing horizontal and curved incisions, respectively. The median age for recipients was 43.1 years with six pediatric cases included in the study. Median operative time was 58 min (43-126 min). The majority of cases required minimal (60.7%) or no drilling (28.6%) with a significant increase in operative time for those requiring moderate drilling versus minimal to no drilling (F = 8.02, p = 0.002). There were no intraoperative complications. One (3.6%) postoperative seroma occurred which resolved with conservative management. CONCLUSION: The proposed modified surgical technique is a safe and effective method for implantation of the transcutaneous BCHA system with a low complication rate. Keys include incision design, implant placement, and two-layered closure to minimize wound tension. These modifications can improve ease of the procedure and reduce operative time. These techniques also appear to be applicable to the pediatric population. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:2401-2404, 2024.

Variables Affecting Cochlear Implant Performance After Loss of Residual Hearing.

OBJECTIVE: Determine variables that influence post-activation performance for cochlear implant (CI) recipients who lost low-frequency acoustic hearing. METHODS: A retrospective review evaluated CNC word recognition for adults with normal to moderately severe low-frequency hearing (preoperative unaided thresholds of ≤70 dB HL at 250 Hz) who were implanted between 2012 and 2021 at a tertiary academic center, lost functional acoustic hearing, and were fit with a CI-alone device. Performance scores were queried from the 1, 3, 6, 12, and 24-month post-activation visits. A linear mixed model evaluated the effects of age at implantation, array length (long vs. mid/short), and preoperative low-frequency hearing (normal to mild, moderate, and moderately severe) on speech recognition with a CI alone. RESULTS: 113 patients met the inclusion criteria. There was a significant main effect of interval (p < 0.001), indicating improved word recognition post-activation despite loss of residual hearing. There were significant main effects of age (p = 0.029) and array length (p = 0.038), with no effect of preoperative low-frequency hearing (p = 0.171). There was a significant 2-way interaction between age and array length (p = 0.018), indicating that older adults with mid/short arrays performed more poorly than younger adults with long lateral wall arrays when functional acoustic hearing was lost. CONCLUSION: CI recipients with preoperative functional low-frequency hearing experience a significant improvement in speech recognition with a CI alone as compared to preoperative performance-despite the loss of low-frequency hearing. Age and electrode array length may play a role in post-activation performance. These data have implications for the preoperative counseling and device selection for hearing preservation candidates. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:1868-1873, 2024.

Noninvasive Treatment of Venous Pulsatile Tinnitus with an Internal Jugular Vein Compression Collar.

OBJECTIVE: The study was conducted to evaluate the safety and efficacy of mild internal jugular (IJV) compression via an FDA approved compression collar for symptomatic treatment of venous pulsatile tinnitus. METHODS: This is a prospective study that recruited 20 adult patients with venous pulsatile tinnitus. Participants completed the Tinnitus Handicap Inventory (THI), were fitted with the collar, and rated symptom intensity on a 10-point tinnitus intensity scale before and during collar use. Once weekly for 4 weeks, they answered a survey quantifying days used, average tinnitus intensity before and after wearing the collar each day of use, and any safety concerns. Lastly, they completed an exit interview. The primary outcome was symptomatic relief, with secondary outcomes of safety, effect of treatment setting, effect of time, and quality of life assessed via nonparametric testing. RESULTS: 18 participants completed the study, and 276 paired daily before use/during use intensity scores were submitted. The median symptom intensity without the collar was 6 (IQR 4, 7), whereas with the collar it was 3 (IQR 2, 5), for a median symptomatic relief of 50%. The collar had a significant effect in reducing symptom intensity (p < 0.0001) and burden of illness via the THI (p < 0.0001). There was no effect of setting, frequency, or time on symptomatic relief with the collar. There were no adverse safety events reported aside from minor discomfort upon initial application. CONCLUSIONS: Venous compression collars offer acute symptom relief for patients with venous pulsatile tinnitus. Further study is needed to assess safety and efficacy of longitudinal use. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:3342-3348, 2024.

Factors that influence performance in pediatric cochlear implant recipients with cochlear nerve deficiency.

OBJECTIVES: Children with cochlear nerve deficiency (CND) have wide variability in outcomes with cochlear implant (CI) use. The current study aims to report a large cohort of pediatric CI recipients with CND and to evaluate for factors that may predict improved performance. METHODS: The current study is a retrospective review of pediatric CI recipients with CND at a tertiary academic hospital. Variables including cochlear nerve status (hypoplasia vs aplasia), age at implantation, cochleovestibular malformation, bony cochlear nerve aperture, internal auditory canal aperture, and cognitive delay were evaluated for predictors of postoperative performance. A stepwise multinomial regression analysis was performed. RESULTS: Forty-seven CI recipients (54 ears) were included in the analysis. A majority (59%) showed auditory capabilities with their CI. Twenty percent of recipients achieved some level of open-set speech perception with their CI. The regression analysis identified cochlear nerve status and cognitive delay as predictors of performance. CI recipients with cochlear nerve hypoplasia had significantly improved performance compared to those with aplasia (p = 0.003). Recipients with cognitive delay had more limited benefit than those without cognitive delay (p = 0.033). CONCLUSIONS: Children with CND can benefit from CI use, with outcomes spanning from non-use to development of spoken language. Predictive factors for improved performance include a lack of cognitive delay and cochlear hypoplasia rather than aplasia. These can be important considerations for parent counseling and decision making.

Demographic Representation in Clinical Research Relative to a Cochlear Implant Patient Population.

OBJECTIVES: Research samples that are representative of patient populations are needed to ensure the generalizability of study findings. The primary aim was to assess the efficacy of a study design and recruitment strategy in obtaining a participant sample that was representative of the broader cochlear implant (CI) patient population at the CI center. A secondary aim was to review whether the CI recipient population was representative of the state population. METHODS: Demographic variables were compared for a research participant sample (n = 79) and the CI patient population (n = 338). The participant sample was recruited from the CI patient population. The study design included visits that were at the same location and frequency as the recommended clinical follow-up intervals. The demographics for the combined group (participant sample and patient population) were then compared to the reported demographics for the population in North Carolina. RESULTS: There were no significant differences between the participant sample and patient population for biological sex, age at implantation, racial distribution, socioeconomic position, degree of urbanization, or drive time to the CI center (p ≥ 0.086). The combined CI recipient population was significantly different from the North Carolina population for the distributions of race, ethnicity, and degree of urbanization (p < 0.001). CONCLUSION: The study design and recruitment strategy allowed for recruitment of a participant sample that was representative of the CI patient population. Disparities in access to cochlear implantation persist, as supported by the significant differences in the combined CI recipient population and the population for our state. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:4101-4110, 2024.

Management of Cochlear Implant Electrode Arrays Misplaced in the Internal Auditory Canal: A Systematic Review.

OBJECTIVE: Misplacement of electrode arrays in the internal auditory canal (IAC) presents a unique clinical challenge. Speech recognition is limited for cochlear implant (CI) users with misplaced arrays, and there are risks with revision surgery including facial and/or cochlear nerve injury. DATABASES REVIEWED: PubMed, Embase, and Scopus. METHODS: A literature search was performed from inception to September 2023. The search terms were designed to capture articles on misplaced arrays and the management options. Articles written in English that described cases of array misplacement into the IAC for children and adults were included. The level of evidence was assessed using Oxford Center for Evidence Based Medicine guidelines. Descriptive statistical analyses were performed. RESULTS: Twenty-eight cases of arrays misplaced in the IAC were identified. Thirteen (46%) were patients with incomplete partition type 3 (IP3), and 7 (25%) were patients with common cavity (CC) malformations. Most misplaced arrays were identified postoperatively (19 cases; 68%). Of these cases, 11 (58%) were managed with array removal. No facial nerve injuries were reported with revision surgery. Eight cases (42%) were left in place. Several underwent mapping procedures in an attempt improve the sound quality with the CI. CONCLUSION: Electrode array misplacement in the IAC is a rare complication that reportedly occurs predominately in cases with IP3 and CC malformations. Removal of misplaced arrays from the IAC reportedly has not been associated with facial nerve injuries. Cases identified with IAC misplacement postoperatively can potentially be managed with modified mapping techniques before proceeding with revision surgery.

Speech Recognition and Subjective Hearing Abilities for Electric-Acoustic Stimulation Users With Unilateral Hearing Loss.

OBJECTIVE: Some cochlear implant (CI) recipients with unilateral hearing loss (UHL) have functional acoustic hearing in the implanted ear, warranting the fitting of an ipsilateral electric-acoustic stimulation (EAS) device. The present study assessed speech recognition and subjective hearing abilities over time for EAS users with UHL. STUDY DESIGN: Prospective, repeated-measures. SETTING: Tertiary referral center. PATIENTS: Adult CI recipients with normal-to-moderate low-frequency acoustic thresholds in the implanted ear and a contralateral pure-tone average (0.5, 1, and 2 kHz) ≤25 dB HL. MAIN OUTCOME MEASURES: Participants were evaluated preoperatively and at 1, 3, and 6 months post-activation. Speech recognition for the affected ear was evaluated with CNC words in quiet. Masked speech recognition in the bilateral condition was evaluated with AzBio sentences in a 10-talker masker (0 dB SNR) for three spatial configurations: target from the front and masker either colocated with the target or presented 90 degrees toward the affected or contralateral ear. Responses to the Speech, Spatial, and Qualities of Hearing Scale subscales were used to assess subjective hearing abilities. RESULTS: Participants experienced significant improvements in CNC scores ( F(3,13) = 14.90, p < 0.001), and masked speech recognition in the colocated ( F(3,11) = 3.79, p = 0.043) and masker toward the contralateral ear ( F(3,11) = 4.75, p = 0.023) configurations. They also reported significantly better abilities on the Speech Hearing ( F(3,13) = 5.19, p = 0.014) and Spatial Hearing ( F(3,13) = 10.22, p = 0.001) subscales. CONCLUSIONS: Adults with UHL and functional acoustic hearing in the implanted ear experience significant improvements in speech recognition and subjective hearing abilities within the initial months of EAS use as compared with preoperative performance and perceptions.

Benefits of Cochlear Implantation for Older Adults With Asymmetric Hearing Loss.

OBJECTIVE(S): FDA-approved indications for cochlear implantation include patients with severe-to-profound unilateral hearing loss (UHL) or asymmetric hearing loss (AHL); however, these indications are not covered for Medicare beneficiaries. We assessed the outcomes of cochlear implant (CI) use for older adults with UHL or AHL. METHODS: Eighteen older adults (≥65 years of age at surgery) with UHL/AHL participated in a prospective, longitudinal investigation evaluating outcomes of CI use. Speech recognition for the affected ear was evaluated with consonant-nucleus-consonant (CNC) words. Spatial hearing was assessed with measures of sound source localization and sentence recognition in noise. The target sentence was presented from the front and the masker was either co-located with the target (SoNo), presented toward the affected ear (SoNci) or contralateral ear (SoNcontra). Perceived benefit was assessed with the Speech, Spatial, and Qualities of Hearing scale (SSQ) and the Tinnitus Handicap Inventory (THI). RESULTS: Participants experienced significant improvements with CI use for CNC words (mean [SD]; preop: 8% [10%], 1 yr: 51% [22%], 5 yr: 50% [19%]), masked sentence recognition (SoNcontra preop: 5% [6%], 1 yr: 22% [15%], 5 yr: 41% [14%]), and localization (preop: 76° [18°], 1 yr: 40° [11°], 5 yr: 41° [14°]), and reported significant improvements in hearing abilities (SSQ Spatial Hearing preop: 3 [1], 1 yr: 6 [2], 5 yr: 6 [2]) and tinnitus severity (THI preop: 16 [18], 1 yr: 4 [14], 5 yr: 6 [12]). CONCLUSION: Older adults with UHL/AHL experience significant improvements in speech recognition, spatial hearing, and subjective perceptions (e.g., hearing abilities and tinnitus severity) with a CI as compared to pre-operative abilities. LEVEL OF EVIDENCE: IV Laryngoscope, 2024.

Incidence of Cochlear Implant Electrode Contacts in the Functional Acoustic Hearing Region and the Influence on Speech Recognition with Electric-Acoustic Stimulation.

OBJECTIVES: To investigate the incidence of electrode contacts within the functional acoustic hearing region in cochlear implant (CI) recipients and to assess its influence on speech recognition for electric-acoustic stimulation (EAS) users. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: One hundred five CI recipients with functional acoustic hearing preservation (≤80 dB HL at 250 Hz). INTERVENTIONS: Cochlear implantation with a 24-, 28-, or 31.5-mm lateral wall electrode array. MAIN OUTCOME MEASURES: Angular insertion depth (AID) of individual contacts was determined from imaging. Unaided acoustic thresholds and AID were used to calculate the proximity of contacts to the functional acoustic hearing region. The association between proximity values and speech recognition in quiet and noise for EAS users at 6 months postactivation was reviewed. RESULTS: Sixty percent of cases had one or more contacts within the functional acoustic hearing region. Proximity was not significantly associated with speech recognition in quiet. Better performance in noise was observed for cases with close correspondence between the most apical contact and the upper edge of residual hearing, with poorer results for increasing proximity values in either the basal or apical direction ( r14 = 0.48, p = 0.043; r18 = -0.41, p = 0.045, respectively). CONCLUSION: There was a high incidence of electrode contacts within the functional acoustic hearing region, which is not accounted for with default mapping procedures. The variability in outcomes across EAS users with default maps may be due in part to electric-on-acoustic interference, electric frequency-to-place mismatch, and/or failure to stimulate regions intermediate between the most apical electrode contact and the functional acoustic hearing region.

Long-Term Binaural Hearing Improvements for Cochlear Implant Users with Asymmetric Hearing Loss.

OBJECTIVE: To assess long-term binaural hearing abilities for cochlear implant (CI) users with unilateral hearing loss (UHL) or asymmetric hearing loss (AHL). METHODS: A prospective, longitudinal, repeated measures study was completed at a tertiary referral center evaluating adults with UHL or AHL undergoing cochlear implantation. Binaural hearing abilities were assessed with masked speech recognition tasks using AzBio sentences in a 10-talker masker. Performance was evaluated as the ability to benefit from spatial release from masking (SRM). SRM was calculated as the difference in scores when the masker was presented toward the CI-ear (SRMci ) or the contralateral ear (SRMcontra ) relative to the co-located condition (0°). Assessments were completed pre-operatively and at annual intervals out to 5 years post-activation. RESULTS: Twenty UHL and 19 AHL participants were included in the study. Linear Mixed Models showed significant main effects of interval and group for SRMcontra . There was a significant interaction between interval and group, with UHL participants reaching asymptotic performance early and AHL participants demonstrating continued growth in binaural abilities to 5 years post-activation. The improvement in SRM showed a significant positive correlation with contralateral unaided hearing thresholds (p = 0.050) as well as age at implantation (p = 0.031). CONCLUSIONS: CI recipients with UHL and AHL showed improved SRM with long-term device use. The time course of improvement varied by cohort, with the UHL cohort reaching asymptotic performance early and the AHL cohort continuing to improve beyond 1 year. Differences between cohorts could be driven by differences in age at implantation as well as contralateral unaided hearing thresholds. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:1480-1485, 2023.

Cochlear Implantation for Unilateral and Asymmetric Hearing Loss: Long-Term Subjective Benefit.

OBJECTIVES: Assess the long-term patterns of perceived tinnitus severity and subjective benefit for adult cochlear implant (CI) users with asymmetric or unilateral hearing loss (AHL or UHL). METHODS: Forty adults underwent cochlear implantation as part of a prospective clinical trial assessing the outcomes of CI use in cases of AHL (n = 20) and UHL (n = 20). Subjective measures included the Tinnitus Handicap Inventory (THI), the Speech, Spatial, & Qualities of Hearing Scale (SSQ), and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Responses were obtained preoperatively and at routine intervals out to 5 years post-activation. RESULTS: For subjective benefit, participants with AHL and UHL reported a significant improvement as compared to preoperative abilities, which was maintained with long-term CI use. For perceived tinnitus severity, participants with AHL and UHL reported a significant reduction with CI use as compared to preoperative perceptions. The perceived tinnitus severity significantly differed for the AHL and UHL cohorts over time. This pattern of results is likely influenced by the worse perceived severity levels for the UHL cohort preoperatively and the fluctuating perceived severity levels for some participants in the AHL cohort post-activation. CONCLUSION: Adults with AHL and UHL report an early, significant reduction in perceived tinnitus severity and improvement in quality of life with CI use that is generally maintained with long-term device use. Questionnaires such as the THI, SSQ, and APHAB may contribute to a more holistic assessment of the benefits of cochlear implantation in this population. LEVEL OF EVIDENCE: 2 Laryngoscope, 133:2792-2797, 2023.

Influence of the Frequency-to-Place Function on Recognition with Place-Based Cochlear Implant Maps.

OBJECTIVE: Comparison of acute speech recognition for cochlear implant (CI) alone and electric-acoustic stimulation (EAS) users listening with default maps or place-based maps using either a spiral ganglion (SG) or a new Synchrotron Radiation-Artificial Intelligence (SR-AI) frequency-to-place function. METHODS: Thirteen adult CI-alone or EAS users completed a task of speech recognition at initial device activation with maps that differed in the electric filter frequency assignments. The three map conditions were: (1) maps with the default filter settings (default map), (2) place-based maps with filters aligned to cochlear SG tonotopicity using the SG function (SG place-based map), and (3) place-based maps with filters aligned to cochlear Organ of Corti (OC) tonotopicity using the SR-AI function (SR-AI place-based map). Speech recognition was evaluated using a vowel recognition task. Performance was scored as the percent correct for formant 1 recognition due to the rationale that the maps would deviate the most in the estimated cochlear place frequency for low frequencies. RESULTS: On average, participants had better performance with the OC SR-AI place-based map as compared to the SG place-based map and the default map. A larger performance benefit was observed for EAS users than for CI-alone users. CONCLUSION: These pilot data suggest that EAS and CI-alone users may experience better performance with a patient-centered mapping approach that accounts for the variability in cochlear morphology (OC SR-AI frequency-to-place function) in the individualization of the electric filter frequencies (place-based mapping procedure). LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3540-3547, 2023.

Cochlear implantation for paediatric and adult cases of unilateral and asymmetric hearing loss.

PURPOSE OF REVIEW: Children and adults with unilateral or asymmetric hearing loss (UHL/AHL) have poorer spatial hearing (e.g. speech understanding in complex maskers and localization) and quality of life compared with peers with normal hearing bilaterally. Patients with UHL/AHL experience limited benefits with contralateral-routing technologies (e.g. bone conduction, CROS hearing aid systems). Cochlear implantation allows for stimulation of the auditory pathway for the poorer hearing ear. The present study reviews the recent literature on outcomes of cochlear implant use for recipients with UHL/AHL. RECENT FINDINGS: Recent research corroborates previous investigations of the significant benefits on measures of spatial hearing, tinnitus severity and quality of life for adult cochlear implant recipients. These benefits are also observed in pediatric cochlear implant recipients, with an association of better outcomes with younger ages at implantation for congenital cases and shorter durations of UHL/AHL for acquired cases. In addition, randomized trials demonstrate better outcomes with cochlear implant use versus contralateral-routing technologies. SUMMARY: Cochlear implantation supports better spatial hearing and quality of life in children and adults with UHL/AHL as compared to alternative listening conditions. Current research supports the expansion of candidacy criteria and insurance coverage for cochlear implantation for patients with UHL/AHL to improve their binaural hearing.

Frequency Mapping of a Precurved Electrode Array in the Internal Auditory Canal for a Pediatric Cochlear Implant Recipient.

OBJECTIVES: Review the effectiveness of an alternative mapping procedure of a precurved electrode array in the internal auditory canal (IAC). DESIGN: A 7-year-old bilateral cochlear implant (CI) recipient of precurved arrays transferred to the study site and demonstrated no speech recognition with the left CI. Imaging revealed bilateral incomplete partition type III malformations. For the left CI, four contacts were observed in the basal cochlear turn and 18 contacts were coiled in the IAC. The family decided against revision surgery. Pitch ranking was completed to map the contacts in the IAC that were perceptually discrete and tonotopically organized. RESULTS: For the left CI, PB-K word recognition improved from no recognition to 32% after 1 month and to 52% after 3 months. In the bilateral CI condition, performance improved from 56 to 72% after 1 month and 80% after 3 months. CONCLUSION: A precurved array in the IAC creates difficult management decisions. Direct stimulation of the auditory nerve resulted in better monaural and bilateral speech recognition, likely due to better spectral representation of the speech signal. Individualizing the map using imaging and behavioral findings may improve performance for malpositioned arrays when revision surgery is not pursued.

Long-Term Improvement in Localization for Cochlear Implant Users with Single-Sided Deafness.

OBJECTIVES/HYPOTHESIS: To assess whether early, significant improvements in sound source localization observed in cochlear implant (CI) recipients with normal hearing (NH) in the contralateral ear are maintained after 5 years of CI use. STUDY DESIGN: Prospective, repeated measures study. METHODS: Participants were recruited from a sample of CI + NH listeners (n = 20) who received their device as part of a prospective clinical trial investigating outcomes of CI use for adult cases of single-sided deafness. Sound source localization was assessed annually after the clinical trial endpoint (1-year post-activation). Listeners were asked to indicate the perceived sound source for a broadband noise burst presented randomly at varied intensity levels from one of 11 speakers along a 180° arc. Performance was quantified as root-mean-squared (RMS) error. RESULTS: Linear mixed models showed superior post-activation performance was maintained with long-term CI use as compared to preoperative abilities (P < .001). Unexpectedly, a significant improvement (P = .009) in sound source localization was observed over the long-term post-activation period (1-5 years). To better understand these long-term findings, the response patterns for the 11 participants who were evaluated at the 1- and 5-year visits were reviewed. This subgroup demonstrated a significant improvement in RMS error (P = .020) and variable error (P = .031), indicating more consistent responses at the 5-year visit. CONCLUSION: Adult CI + NH listeners experience significant improvements in sound source localization within the initial weeks of listening experience, with additional improvements observed after long-term device use. The present sample demonstrated significant improvements between the 1-year and 5-year visits, with greater accuracy and consistency noted in their response patterns. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:2453-2458, 2022.